使用usort和自定义比较函数的多维数组/对象排序

Posted 2021-02-24

<?php
 
/**
 * 
 * EXAMPLE #1
 *
 * sort array of objects based on specified attribute values
 * in this case "lastname", followed by "firstname"
 * 
 **/
 
$person1 = (object) array('lastname' => 'Jones', 'firstname' => 'Michael', 'Degree' => 'AAA');
$person2 = (object) array('lastname' => 'Adams', 'firstname' => 'Zach', 'Degree' => 'BB');
$person3 = (object) array('lastname' => 'Smith', 'firstname' => 'Jim', 'Degree' => 'CCC');
$person4 = (object) array('lastname' => 'Adams', 'firstname' => 'Tom', 'Degree' => 'DD');
 
$array_to_be_sorted = array( $person1, $person2, $person3, $person4);
 
echo "Before";
echo "<pre>";
print_r($array_to_be_sorted);
echo "</pre>";
echo "<br /><br />";
 
function alpha_sort($a, $b) {
 
    if ($a->lastname == $b->lastname) {
        return strnatcmp($a->firstname, $b->firstname);
    }
    return strnatcmp($a->lastname, $b->lastname);
}
 
usort($array_to_be_sorted, "alpha_sort");
 
echo "After";
echo "<pre>";
print_r($array_to_be_sorted);
echo "</pre>";
 
?>
 
<?php
 
/**
 * 
 * EXAMPLE #2
 *
 * sort array of arrays based on specified array keys
 * in this case "lastname", followed by "firstname"
 * 
 **/
 
 
$array_to_be_sorted = array(
    array('lastname' => 'Jones', 'firstname' => 'Michael'),
    array('lastname' => 'Adams', 'firstname' => 'Zach'),
    array('lastname' => 'Smith', 'firstname' => 'Jim'),
    array('lastname' => 'Adams', 'firstname' => 'Tom')
);
 
function alpha_sort($a, $b) {
 
    if ($a['lastname'] == $b['lastname']) {
        return strnatcmp($a['firstname'], $b['firstname']);
    }
    return strnatcmp($a['lastname'], $b['lastname']);
}
 
usort($array_to_be_sorted, "alpha_sort");
 
echo "<pre>";
print_r($array_to_be_sorted);
echo "</pre>";
 
?>